Path: csiph.com!fu-berlin.de!uni-berlin.de!individual.net!not-for-mail From: "Carlos E. R." Newsgroups: comp.os.linux.misc,alt.comp.os.windows-11 Subject: Re: Real-time OSs (Re: Microsoft Is Abandoning Windows 11 SE) Date: Wed, 13 Aug 2025 12:45:26 +0200 Lines: 50 Message-ID: References: <106mke5$1di32$1@dont-email.me> <3ihcmlx47d.ln2@Telcontar.valinor> <107070d$3hvho$1@dont-email.me> <1071hb2$3qqje$2@toylet.eternal-september.org> <1071jbr$3ra8s$1@dont-email.me> <10746fg$h625$2@dont-email.me> <20250808081850.00002e14@gmail.com> <1075pla$ukab$1@dont-email.me> <20250808144937.000021b1@gmail.com> <10761aq$vv6o$3@dont-email.me> <10777f7$17kq4$8@dont-email.me> <6uqkmlxjb8.ln2@Telcontar.valinor> <1079oe9$1ppd6$6@dont-email.me> <107ab26.3rg.1@ID-201911.user.individual.net> <3rkmmlxplv.ln2@Telcontar.valinor> <107cipt$2g8mr$9@dont-email.me> <107ghmk$3j56j$4@dont-email.me> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit X-Trace: individual.net FiBO1rfLn/yPUaYtS3bJHgl/qQehNG9cmbWcDZlFvY05bbk3Kp Cancel-Lock: sha1:KH+dLyEJkEJXCOh+iS0WXIXiq9Q= sha256:nD8UKvh0SUwkZGJtFphh18T/aqxAurNpenwnXJRp4Bo= User-Agent: Mozilla Thunderbird Content-Language: en-CA, es-ANY In-Reply-To: Xref: csiph.com comp.os.linux.misc:70910 alt.comp.os.windows-11:22012 On 2025-08-13 04:11, Lars Poulsen wrote: > On 2025-08-11 13:05, The Natural Philosopher wrote: >>>> As soon as you are running real time shit under a multitasking system >>>> even giving high priority to real time tasks cannot guarantee they get >>>> dealt with in exact time frames. > > On Tue, 12 Aug 2025 10:56:49 +0200, Carlos E. R. wrote: >>> It did. If it failed, long distance phone calls would not work. > > On 2025-08-12, Lawrence D'Oliveiro wrote: >> I wonder about that. A lot of telephony providers are using VoIP nowadays, >> and several of the common VoIP/telephony engines (e.g. Asterisk, Kamailio) >> are open-source and run on Linux. And not even specially-tuned “real-time” >> Linux systems, at that -- they are available as standard packages under >> Debian and derivatives, for example. >> >> All this works fine for long-distance calls, local calls, value-add >> services like IVR, voice mail etc. Even video calling, if you want. > > Asterisk PBX software on Linux works ... because it is packet switching > software, not circuit switching. It may work less well in a deskset, > driving the signal chain microphone->A/D converter->packetizer and its > counterpart on the receiving end. > > VoIP over intercontinental distances has some issues, especially with > cheap providers. Lossy circuits have dropouts, or if they try too hard > to cover themup with retransmissions, they gradually build up delays > that get long enough to interfere with dialogue flow. Telcos systems were subject to strict quality control systems, that worked. VoIP systems are not. As an example that anybody can see, the terminals at home had their own power. Even if the nation had a full power failure, the telephone network kept running. Anybody could phone emergencies or his cousin. > > My "4 guys in a garage" company for years was selling a gateway that > bridged T1 or synchronous serial RS422 over the Internet ... or at least > over TCP/IP networks. I learned a lot about managing delay and jitter > while working on that product. Like our radio products, it ran our own > RTOS in order to be close enough to the hardware to know the worst case > interrupt latency by counting instructions in the interrupt dispatcher. > If your interrupt latency is longer, you have to put more processing > into an ASIC or FPGA. -- Cheers, Carlos E.R.